Bus bars of the generic type are known in basic principle, so that a separate documentation of publications for this is not needed. Bus bars, often also referred to as collecting bars, are components in the electrical energy supply and serve for conveying electrical energy due to a current flow from the first electrical device to the second electrical device or vice versa. Electrical devices can be, for example, electrical consumer devices, in which the supplied electrical energy is utilized for implementation of an intended function, as well as energy sources, such as, for example, electrical generators based on electric machines, optoelectric converters, such as, for example, solar cells or the like, fuel cells, and/or the like. Bus bars have, besides a high electrical conductivity, an appropriate mechanical strength, so that the influence of mechanical forces, such as those that can occur, for example, in the case of overcurrents, can be conveyed by the bus bar, without the intended function thereof being substantially impaired. Beyond this, bus bars can often withstand high thermal loads, so that, in thermally exposed areas, they can also execute their intended function substantially in a reliable manner. The bus bar generally has a base body made of an electrically conductive material, which provides terminals for the electrical devices, such as the first electrical device and the second electrical device. Used as material is often a metal such as aluminum, copper, alloys thereof with, if need be, other metals, and/or the like. Moreover, bus bars are components in electrical engineering that are relevant to safety, for which reason they are included in, among other things, standards specifications, such as, for example, in DIN 43671, DIN 43673, DIN 43771, and others. However, bus bars find use not only in stationary energy distribution, but also, beyond this, in electrical systems of motor vehicles as well as in other electrical devices in which electrical energy is distributed, particularly on a large scale.
Thus, for example, the utilization of bus bars is also common in the case of batteries that comprise at least two battery cells. A battery cell is a device that has two electrodes that interact electrochemically with each other. The interaction can occur under supplemental assisting action of an electrolyte. Battery cells, which are also referred to as galvanic cells, are preferably reversible in terms of their function, such as occurs, for example, when batteries in the form of rechargeable batteries or the like are employed. On account of the electrochemical interaction of the electrodes, a direct current voltage that is specific for the particular battery cell chemistry is created and is supplied to the terminal contacts of the respective battery cell that are connected to the electrodes. This direct current voltage is generally relatively low. Many applications in electrical engineering necessitate a direct current voltage that markedly exceeds the direct current voltage that can be supplied by a single battery cell. For this reason, a plurality of battery cells are often combined to form a battery and electrically connected within the battery in accordance with the electrical requirements, for example in the form of a serial connection, a parallel connection, combinations thereof, or the like.
Within the battery, the individual battery cells are therefore connected in an electrically conductive manner by means of bus bars in the desired kind of circuit in order to be able to supply the desired direct current voltage to the terminal poles of the battery. Such batteries are employed, for example, as lead acid batteries in the motor vehicle sector, as nickel cadmium batteries in the aircraft sector, and, for interruption-free supply of current, as lithium ion batteries in the sector of small household appliances and/or the like, but also recently for electrically driven motor vehicles.
Motor vehicles of the generic type are also well known. Preferably, motor vehicles comprise those that have an electrical system with a battery as well as a drive device connected to the electrical system. Such motor vehicles are, for example, electric vehicles, hybrid vehicles, in which a drive operation is possible both by means of an electric drive device and by means of a combustion engine, or the like. In these motor vehicles, the battery and the drive device each have at least two electric terminal contacts. For the purpose of electric coupling, at least one of the terminal contacts of the battery and one of the terminal contacts of the drive device are connected to each other in an electrically conductive manner by means of an electrical bus bar. In this case, too, the electrical bus bar is formed by an electrically conductive base body.
Even though the prior art has proven itself, there are nonetheless problems, in particular for use in motor vehicles. Thus, a common practice is to detect or record the current that is applied to a bus bar by means of a current transformer unit. The current transformer unit is an electrical component that, by means of a magnetically permeable annular core, records the magnetic field produced by a current flowing through the bus bar and provides a corresponding measurement signal. Such a current transformer unit generally has a relatively heavy weight as well as also a large structural form. This poses an obstacle and is undesired especially in the field of electromobility. Moreover, the large structural form and the heavy weight lead to problems, especially in the field of electromobility in regard to exposure to vibrations and impacts, such as those usually occurring during the intended operation of motor vehicles.
Alternatively, it is known to record the current flow through the bus bar by means of a shunt. For this purpose, the bus bar is divided into two base bodies, which are connected to each other in an electrically conductive manner by means of the shunt. Although it is possible in this way to obviate the aforementioned complicated current transformer unit and the problems caused by it, this embodiment, however, has proven detrimental insofar as the shunt must be engaged in the bus bar, the consequence of which is not only a great effort, but, beyond this, is also undesired on account of the high current load placed on the bus bar in intended operation. The required contacting points in the area of the shunt result in additional problems in terms of safety and reliability.